1. Field of the Invention
The invention relates to a firefighting bucket assembly to be suspended from an aircraft and preferably filled from an open body of water, ie. from a lake.
2. Prior Art
From U.S. Pat. No. 3,661,211 Powers is known for a collapsible fire fighting bucket, which could be filled by immersion in a lake.
The bucket framework which supported its pliable side walls had four normally upright but collapsible supports connecting a rigid upper peripheral frame member to a ridged circular bottom. The water level being controlled by spill ports to adjust overall bucket weight to match the lifting capabilities of the aircraft. Two hydraulically operated doors released the water. When collapsed the bucket was bulky, difficult to transport, additionally the water release mechanism was heavy and expensive to manufacture. From U.S. Pat. No. 3,572,441 issued to Nodegi describes a flexible bag having a snout like flexible extension which when pulled into the bag from a line entering the top of the bag had to keep the free end of the tubular snout like extension above water. When the line was released the weight of the water inverted the tubular extension thereby releasing the water. When empty the connecting line was made to pull the extension back into the bag where a latching system held it in place.
The disadvantages of this system were the discharge port had to be held above the water level of the bag, the length of the extension caused a twisting action which could prevent dumping. In order to refill the bag it had to be transported to a filling station which resulted in loss of time increasing operational costs accordingly.
The bucket assembly described in Arney's CA 1232889 and U.S. Pat. No. 4,474,245 revolutionized aerial firefighting operations. Its simple design, lightweight, its collapsability for storage and transportation, operational superiority over prior art, has redefined aerial firefighting technologies.
Arney's invention has two bucket adjusting means which co-operate with the side wall to adjustably vary the circumference of the bucket. Firstly; bending battens inserted in pockets vertically arranged around the bucket and dimensioned apart peripherally allow the side walls to bulge outwardly to increase capacity in direct relationship to the upward force applied, allowing the operator to match the lifting capability of the helicopter to the overall weight of the bucket. This feature helped eliminate the need for spill ports utilized by Powers in U.S. Pat. No. 3,661,211 or that purpose—Secondly; independently from varing the pulling force as described above to limit bucket capacity Arney introduced an adjustable circumferential tension link. A cinch belt slidably received in belt loops around the bucket's circumference can be adjusted to limit its capacity. The operator simply adjusts bucket capacity to lifting capability of the helicopter by adjusting the cinch belt in the lockable cinch belt adjuster.
The bucket rim was stiffened by overlapping battens strung through belt loops placed around and adjacent to bucket rim. Operationally this proved to be a time consuming awkward task, begging for improvement.
Arney's improvement on Nodegi U.S. Pat. No. 3,572,441 involved sealing the discharge ports of the tubular extension when it's underwater, upright and under tension from its supporting means. Third flexible tension links, purse lines, alternately affixed through opposing resilient sealing lips closed the discharge port when under tension from the supporting tension link which is adjustably connected to the electro-mechanical control head connector which the operator utilizes to open & close the discharge port for filling and releasing water.
Needham's CA 2,124,166 and U.S. Pat. No. 5,670,429 improved the sealing lip abutment to reduce leakage caused by placing the grommets in the tubular extension adjacent to the resilient sealing lips which eliminated having the purse lines running through the resilient sealing lips, thereby eliminating abrasion to the rather soft resilient sealing lip material.
This abrasion increased the tubular extension maintenance factor. The entire tubular extension required removal from the bucket for this servicing, which in many cases required returning the bucket to the manufacturer, transportation and downtime causing additional expense.
Despite Needham's improvements to the sealing lip design further design changes could reduce water leakage through the sealing lips. One problem exists with a kink appearing in the distal end of the tubular extension when it's under tension from the second flexible link which holds the tubular extension in the underwater upright position. The kinked shape in some cases can be severe, especially if the third flexible tension links are poorly adjusted. The kinking occurs as a result of the third flexible tension links ie, the purse lines being gathered together at the terminal end of the second flexible tension link ie. in the ring to which the purse lines are adjustably connected. The purse lines fan out radially downward from the single collection point ie, the ring, to the dimensionally arranged openings in the tubular extension extending to the essentially horizontal distal ends of the tubular extension.
The outermost purse lines under tension are sharply angled upward from the outer ends of the tubular extension toward the collector ring. This generates an inwardly movement of the outermost ends of the tubular extension when under tension from the second flexible tension link, which causes the fold or kink to occur which can effect the proper alignment and abuttment of the sealing lips with potential water loss associated. Larger buckets with wider tubular extensions are more prone to this problem because the angle of the purse lines is increased accordingly at their distal ends. As the purse lines pass downwardly from the second flexible tension link ring through the hub the outermost lines become diverted by the hub increasing the angle and further developing a pronounced kink. The reader is directed to the SEI Industries Ltd. copyrighted Owners Manual produced in April 1999 which pictures both of these problems.
One objective of the Rim Opening Device invention is to reduce purse line abrasion on the sealing lips as they pass through the sealing lips similar to Arney's CA 1232889 and U.S. Pat. No. 4,474,245 submissions.
Another objective of the Rim Opening Device invention was to eliminate the central hub which diverts and increases the purse line angle to the collector ring which exacerbates the kink and potential water loss through misaligned sealing lips.
Needham's tubular extension was made narrower at its terminal end than at its base to assist the tubular extensions return to its upright position within the bucket. This change was limited to the smaller buckets only, due to the stiffness associated with smaller tubular extensions.
Larger diameter tubular extensions utilized on both medium and large buckets being more flexible were not affected, no change in the straight diameter design was required.
Another objective of the Rim Opening Device invention is to make the tubular extensions more flexible to assist the tubular extension's return to its upright position within the bucket.
The aerial firefighting condition can aggressively subject the aerial firefighting bucket to physical damage. Ideally the bucket is allowed to submerge in an open body of water for filling purposes.
The operators often find it necessary to scrounge water from any available source ie, shallow ponds, creekbeds, rivers, etc. where all manner of conditions and debris can inflict damage to the bucket. A typical example would be dragging the bucket along a shallow creekbed or river filled with sharp rocks, gravel, mud, uprooted trees, etc. This subjects the buckets upper rim, side walls & bottom of the bucket to aggressive abrasion, which can cause ripping and tearing of the pliable material. It has been found that both debris and bucket suspension lines can get entangled and hung up on the centrally located hub and spoke Rim Opening Device, resulting in lost time to land and re-configure lines and remove debris.
Other damage can occur in operational conditions such as impact, hard landings, hangups, emergency release of entire bucket when snagged or hung up.
It's just the nature of the business, however; design changes can mitigate physical damage to the aerial firefighting bucket.
Another objective of the Rim Opening Device invention is to totally eliminate the hub and spokes or any structural members centrally located within the bucket, producing a collapsible bucket with a centrally open orifice.
The central hub and spoke rim opened device which Needham describes in CA 2124166 and U.S. Pat. No. 5,560,429 can prove to be difficult to deploy on the larger buckets which are constructed of heavier, stiffer materials than their smaller counterparts.
The operator must muscle the hub & spoke rim opener into the overcenter position by fighting the stiff action and tightfitting device past center. It is sometimes necessary to utilize a lever to pop it center, when it does so it either quickly jumps out at you or plunges inward, care must be taken in its deployment.
Needham also describes in Claim 7 and lines 38 et., of column 4 of the Detailed Description in the above noted patents, a Rim Opening Device. It comprises of a hollow hub centrally located and having a plurality of spokes which have their inner ends hinged from the central hub. They extend radially with their outer ends hinged adjacent the bucket rim and cooperating with the side wall to open and close the bucket somewhat like an umbrella. The spokes being dimensioned such as to allow an overcentering of the hub and spokes slightly above the bucket rim elevation. This device marked a significant improvement over Arney's upper rim stiffening batten system as described in this CA 1232889 and U.S. Pat. No. 4,474,245. However the umbrella like hub and spoke device is not without shortcomings.
Another objective of our Rim Opening Device invention is to improve not only the deployment and collapsibility of the bucket but also operational safety while undertaking these activities in the field of operations.
Needham's bucket mouth held open by a hub and spoke apparatus was a great improvement over the prior art of the time. The distal ends of the spokes dimensionally connected around the rim provide rim support at the connection point which assists the immersion process. However, Needham's bucket has some tendency to float on the surface prior to immersion. There are two reasons for this phenomenon, firstly; the rim is made of quite flexible material and is not supported between the distal ends of the spokes to which it is connected, the flexible material is pushed upward upon laying down rather than quickly penetrating the surface, secondly; both Arney's and Needham's tipping weight systems connects weight shot bags or blocks to the shell of the bucket, somewhat below the rim, their weight distending the shell curvature when laid horizontally on the water. The distended shape forms a shallow hull which promotes floating not submersion slowing the filling process.
Another objective of our Rim Opening Device invention was to truly achieve rapid submersion and filling, overcoming the above noted phenomenon by re-enforcing the rim, buttressing the rim circumferentially and by concentrating the tipping weights right at the rim not below it to achieve this objective.
A significant problem exists with Needham's CA2,124,166 and U.S. Pat. No. 5,670,429 umbrella-like bucket opening device which is water loss out of the bucket during flight. Water loss being caused by a constant undesirable flexing of the bucket shell, a repetitive in and out action generated at the bucket's rim, but transferred throughout the entire bucket disturbing the contained water, and transmitting a harmonic vibration that can sometimes be felt all the way up to the helicopter.
Both the deployment cable that lifts the hub into the operational position and the bucket's suspension lines are under tension from the electro-mechanical control head connector to which they are dually attached. Now the overcentered centrally located hub radially connects the distal ends of the inclined spokes to the perimeter of the bucket shell.
As the prior art bucket moves at speed through the air it is buffeted about and disturbed in flight which causes a back and forth transfer of weight on and off the hub. As the tension on the hub abruptly drops so does the hub, only to be violently jerked back up again; up-down, up-down, over and over again generating an undulating pulsing action.
As the centrally located hub radially connects the spokes to the bucket rim the up and down movement described above causes the perimeter of the bucket rim to move in and out, over and over again. Over time the rotatably connected spokes, brackets and hub connections become worn; holes elongated, oscillated especially when hollow spokes are utilized, the worn parts co-operate to increase the intensity of the undesirable pulsing and harmonic vibrations.
Additionally, because the overcentered hub and upper portions of the inclined spokes are positioned above the bucket's rim they collide with high speed air during flight, redirecting or deflecting the turbulent air into the mouth of the bucket colliding with the agitated water (provoked by the pulsing, undulating, harmonic vibrations) to generate a spray of water out of the bucket, much like a gale force wind will blow the top of a whitecap at sea. The design and positioning of the umbrella like device propagates water loss out of the bucket during flight.
Other objectives of our Rim Opening Device Invention is to create a bucket with superior air flow characteristics which would reduce water loss, eliminate vibrations, pulsing and surging, in general produce superior inflight characteristics which help reduce pilot fatigue.
Another objective of this invention was to provide a simple, inexpensive secondary discharge tube which could be utilized by ground crews to manually fill back packs, water storage bags, small tanks, from a bucket slung from under the helicopter. Currently, there are two methods which this writer is familiar with.    1. an expensive pump system operated by ground crews.    2. a rotatable stiff tube corrected to a through hull rotatable bulkhead fitting the tube extending above the bucket rim when in the upright position, and connected thereto by a quick connector.
Our objective would provide a dual purpose secondary discharge hose, one which is sufficiently flexible to eliminate the need for a rotatable fitting. Additionally, the operator can vary the bucket's capacity by variably connecting the distal end of the hose below the rim on smaller wild fire buckets, eliminating the need to choke the bucket with a cinch strap, which is currently the method. Effectively, this system of adjusting the bucket's capacity is functional for smaller wild fire buckets only, due to the longer drain down time required for larger buckets. This system would be beneficial to buckets such as the 80-90-100-120 gallon variations where 10-30% drain down times are operationally satisfactory.
Another specific objective of this invention was to improve the servicing of the valve in addition to the bucket's general serviceability. A worst case scenario would be removing a damaged valve during field operations. Two factors make this service operation very difficult on prior art buckets. Firstly; the entire umbrella-like bucket opening device, the central hub, spokes, restrainer cable, and deployment cable must be removed to gain access into the bucket to remove the valve's circular ring of fasteners The valve is firmly sealed with butyl tape, bonding the valve collar's resilient material to the bucket shell, Removing the valve, breaking the butyl bond is not only difficult but messy, the butyl compound sticking to anything it touches. Most often breaking this bond results in ripping chunks out of the valve's resilient sealing collar, with some portions remaining adhered to the shell of the bucket. The torn out chunks of the resilient sealing valve collar must be removed, the butyl compound removed and replaced before the new valve can be installed; it's a messy and difficult operation. After the new valve has been installed, the central hub, spokes, restrainer cables and bucket deployment cable must now be re-installed.
The centrally open top of our “Wild Fire Bucket” invention, resolves the first difficulty, while the valve sealing resilient collar's design and installation resolves the latter. The improvement being a two piece sealing device each having a resilient collar. The bottom collar is sealed to the bucket shell in the traditional manner with a butyl type compound, while the upper collar is permanently attached to the valve body. A ring of fasteners bring the collars into sealing abuttment. Removing this type of valve is a simple matter. It's done without disturbing the butyl seal which remains firmly in place during the procedure. The valve can now be replaced by simply turning the bucket upside down and reaching into the bucket. No longer is it necessary to climb into the bucket to change a valve. The new design resolves a long standing service issue.
Another servicing problem exists with Prior Art Buckets, when seriously damaged, the bucket shell or body requires opening it up and cutting out ripper, torn, holed, or otherwise damaged panels for their replacement. To do this requires removing the valve from the bucket. Our design improvement now once again allows the valve to be easily removed without damage. Now, the resilient sealing collars have a fabric cover which protects their soft resilient sealing material. The lower collars can be removed from the bucket's shell or body without being torn or damaged by the butyl sealing compound which resists the removal. The covering saves the lower collar under this servicing.
On occasion water bucket equipped helicopters are dispatched to transport emergency supplies to “Wild Fire Ground Crews”, i.e. back packs, tools and equipment, potable water, first aid supplies, emergency heat shield blankets and bags, etc. Water buckets equipped with constricting hubs and spokes require precious time to stuff the cargo in and through the narrow spaces between the hub and spokes but even more time, sensitive life threatening time, to arduously retrieve the previous cargo under extreme operational conditions.
Another objective of our Rim Opening Device Invention was to design the bucket mouth centrally open, free of obstructions facilitating efficient emergency cargo transport.
However, the single most significant aspect of a centrally open bucket mouth—bar none—is the bucket's emergency adaptability to extract “Wild Fire Ground Crew” Personnel from harms way. Trapped and encircled by a fire storm, it literally becomes a dire straits emergency life saving platform, the centrally open mouth providing firefighting ground crew emergency access into the bucket for safe extraction. Never in the history of collapsible water bucket design and technology has this life saving feature been obtainable.